Apparently at least two casual flight attendants have been stood down in the last week or two by the catins on a330 flights for a demonstrated lack of knowledge of basic emergency proceedures. one a330 skipper I was talking to in the crew room recently,said he is now telling his CM that he will be questioning the casual crew, and will have no problem standing any down that don't know or are unable to explain to him their duties in variou EMG situations.